壳聚糖/羟基磷灰石骨修复材料的研究进展

首先概述了骨组织的成分、结构及功能,继而分别介绍了壳聚糖和羟基磷灰石的结构与性质,包括生物相容性、降解性、抗菌性、骨传导性等,综述了壳聚糖/羟基磷灰石复合材料的制备方法、力学性质、生物性能及研究现状,并对载药骨修复材料的研究作了简要介绍,最后展望了壳聚糖/羟基磷灰石骨修复材料在未来的发展前景.     

羟基磷灰石/胶原蛋白/壳聚糖多孔支架的制备及性能研究

通过共滴定法合成工艺制备出羟基磷灰石/胶原蛋白粉体,以制备的羟基磷灰石/胶原蛋白粉体为原料,选用冷冻干燥成型技术,制备羟基磷灰石/胶原蛋白/壳聚糖复合多孔支架材料.研究结果表明:通过X射线衍射分析和透射电镜分析,羟基磷灰石/胶原蛋白纳米粉体中羟基磷灰石晶粒是针状的弱结晶的晶体,与天然骨中的纳米羟基磷灰石晶粒相近;羟基磷灰石/胶原蛋白/壳聚糖复合多孔支架的抗压强度、孔隙率、平均孔径可达到骨组织工程支架材料的要求,是由有机-无机三相复合、具有三维多孔结构、又有良好机械性能的具有发展潜力的骨支架材料.     

纳米羟基磷灰石/聚酰胺66复合材料药物缓释载体研究

将纳米羟基磷灰石/聚酰胺66(n-HA/PA66)复合材料与抗生素类药物头孢哌酮钠(cefoperazone Sodium)复合,用特定溶剂将其调成糊状并自固化后,对该复合材料负载抗生素后的理化特性进行了研究.通过红外光谱及X射线衍射分析显示,载药材料保持了良好的化学稳定性.扫描电镜图象显示,材料表面及内部结构多孔.自固化n-HA/PA66复合材料在骨修复药物载体方面有很好的开发和应用前景.     

壳聚糖/羟基磷灰石引导组织再生膜材料的制备和性能

用生物矿化交替沉积法成功在CS基质膜表面构建HA涂层,并进行了表征.结果表明,HA含量随着沉积循环数增加而增加,且在4个循环后基本达到饱和,饱和含量为8.8%;随着沉积循环数增加HA由均一颗粒状转变为无规则平板状;拉伸强度由纯CS膜的68.6 MPa降低到沉积5个循环后的46.9 MPa.控制沉积数可调控HA的含量、形貌和力学强度,以满足引导组织再生术需要.     

纳米羟基磷灰石/壳聚糖-羧甲基纤维素复合支架材料的研究

用冷冻干燥法制备了不同比例的纳米羟基磷灰石/壳聚糖-羧甲基纤维素(n-HA/CS-CMC)无机/有机复合多孔支架材料, 并探讨了其复合机理及无机组分n-HA对复合支架的结构形貌、力学性能、体外降解性能的影响. 结果表明, 其复合支架主要是通过无机组分n-HA均匀分散充填在CS-CMC聚电解质有机网络结构中形成的, 且三组分间有较强的化学键合. 无机组分n-HA的加入使孔结构变得不规则, 孔隙率略有减小, 使复合支架的抗压缩强度提高, 并且可使其体外降解速度减慢. 无机组分n-HA含量为40\%复合支架材料的性能最佳, 有望用作骨组织工程支架材料.     

纳米羟基磷灰石-胶原蛋白-壳聚糖复合生物材料

采用共沉淀法制备了纳米羟基磷灰石．胶原蛋白．壳聚糖复合生物材料，用IR、XRD、TEM及万能材料实验机等方法对材料性能进行了分析表征。结果表明：羟基磷灰石．胶原蛋白．壳聚糖复合生物材料在晶相组成、化学成分、羟基磷灰石尺寸上具有类骨结构，并具有良好的力学性能．其抗压强度达到128MPa，可满足骨组织修复与替代的要求。有望成为治疗骨缺损的承力替代物。     

纳米羟基磷灰石/壳聚糖杂化材料的制备

以原位沉积法为基础, 采用水热处理法制备羟基磷灰石(HA)/壳聚糖(CS)杂化材料, 以解决HA在CS基体中分布不均和结合不紧密的问题. 研究表明, 通过水热处理后所得到的杂化材料是由CS分子和低结晶度的HA晶体所组成. 其中HA的晶体尺寸为纳米级, 均匀分布在CS分子中. 而且杂化材料中的HA和CS都出现沿C轴方向的择优生长. 同时还发现, 在所得杂化材料中的HA晶体与CS分子出现了较强的化学键合作用, 且这种化学键合作用的强度随水热处理温度的升高而增强, 其中当水热处理温度为100℃时,这种化学键合作用达到最强.     

多孔羟基磷灰石微球的药物缓释性能

用锂钙硼（LCB）玻璃在磷酸盐溶液中的原位转化反应制备多孔羟基磷灰石（HA）微球,表征微球的物相组成、孔结构和形貌,以溶菌酶为药物模型研究了药物的缓释性能。结果表明,所制备的HA微球具有较好的孔结构。当溶菌酶溶液的浓度较低时,HA微球将溶菌酶吸附在微球的外表面;当浓度较高时,更多的溶菌酶扩散进入HA微球的微孔中,使缓释...     

纳米羟基磷灰石/壳聚糖复合生物材料研究

骨的特殊性能决定了其在人体中起重要的功能作用,人工骨材料对骨缺损的治疗有重要意义。羟基磷灰石是人和动物骨骼的主要无机成分;壳聚糖是天然可降解多糖,降解产物为对人体组织无毒、无害的氨基葡萄糖。纳米羟基磷灰石/壳聚糖复合生物材料可以实现羟基磷灰石和壳聚糖两者的优势互补,具有优良的生物活性、生物相容性和力学性能。介绍了近年来纳米羟基磷灰石/壳聚糖复合生物材料的主要合成方法(如共混法、共沉淀法、原位沉析法、交替沉积法和模拟体液法等),并在此基础上介绍了基于纳米羟基磷灰石/壳聚糖的三元复合材料的研究及发展情况;最后,展望了纳米羟基磷灰石/壳聚糖复合生物材料未来的发展方向。     

ZTS晶体缺陷的实时AFM观测

利用原子力显微镜(AFM)对硫脲硫酸锌(ZTS)(100)面的生长过程进行实时观测研究,发现晶体表面凹陷及杂质对台阶推移的阻碍作用均有可能导致凹坑的出现;大台阶对凹坑和杂质的覆盖是包裹体产生的重要原因。首次观察到杂质分界点现象,不可移动杂质的存在不会终止台阶的推移。     

In vitro evaluation of S-(+)-ibuprofen as drug candidate for intra-articular drug delivery system

Intra-articular drug delivery systems (DDSs) are envisaged as interesting alternative to locally release non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to reduce pain in patients with osteoarthritis. The present study examines the efficacy of S-(+)-ibuprofen on cartilage degradation as drug candidate for DDS loading. Humeral cartilage and joint capsule explants were collected from healthy sheep shoulder joints and they were cultured in mono- or in co-culture for 13?days with LPS in combination with S-(+)-ibuprofen at 50?µM and 1?mM. S-(+)-ibuprofen (50?µM) blocked prostaglandins production in LPS-activated explants but did not reduce cartilage degradation. By contrast, 1?mM S-(+)-ibuprofen treatment of cartilage explants reduced nitric oxide synthesis by 51% (p?=?0.0072), proteoglycans degradation by 35% (p?=?0.0114) and expression of serum amyloid protein – the main protein induced upon LPS challenge – by 44% (p?相似文献   

In vitro and in vivo performance of a multiparticulate pulsatile drug delivery system

The objective of this study was to investigate the in vitro and in vivo drug release performance of a rupturable multiparticulate pulsatile system, coated with aqueous polymer dispersion Aquacoat® ECD. Acetaminophen was used as a model drug, because in vivo performance can be monitored by measuring its concentration in saliva. Drug release was typical pulsatile, characterized by lag time, followed by fast drug release. Increasing the coating level of outer membrane lag time was clearly delayed. In vitro the lag time in 0.1 N HCl was longer, compared to phosphate buffer pH 7.4 because of ionisable ingredients present in the formulation (crosscarmelose sodium and sodium dodecyl sulphate). In vitro release was also longer in medium with higher ion concentration (0.9% NaCl solution compared to purified water); but independent of paddle rotation speed (50 vs.100 rpm). Macroscopically observation of the pellets during release experiment confirms that the rupturing of outer membrane was the main trigger for the onset of release. At the end of release outer membrane of all pellets was destructed and the content completely released.

However, pellets with higher coating level and correspondingly longer lag time showed decreased bioavailability of acetaminophen. This phenomenon was described previously and explained by decreased liquid flow in the lower part of intestine. This disadvantage can be considered as a limitation for drugs (like acetaminophen) with high dose and moderate solubility; however, it should not diminish performance of the investigated system in principle.     

Local drug delivery system for the treatment of osteomyelitis: In vitro evaluation

Local antimicrobial delivery is a potential area of research conceptualized to provide alternative and better methods of treatment for cases, as osteomyelitis where avascular zones prevent the delivery of drugs from conventional routes of administration. Drug-loaded polymers and calcium phosphates as hydroxyapatites have been tried earlier. Bioactive glasses are bone-filling materials used for space management in orthopedic and dental surgery. A new bioactive glass (SSS2) was synthesized and fabricated into porous scaffold with a view to provide prolonged local delivery of gatifloxacin and fluconazole as suitable for the treatment of osteomyelitis. The new SSS2 was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses. In addition, the bioactivity of the SSS2 glass and resulting scaffold was examined by in vitro acellular method and ascertained by FTIR and XRD. The pore size distribution was analysed by mercury intrusion porosimetry and the release of drugs from scaffolds were studied in vitro. The glass and the resulting scaffolds were bioactive indicating that they can bond with bone in vivo. The scaffolds were porous with pores predominantly in the range of 10–60 µm, released the drugs effectively for 6 weeks and deemed suitable for local delivery of drugs to treat osteomyelitis.     

Local drug delivery system for the treatment of osteomyelitis: In vitro evaluation

Local antimicrobial delivery is a potential area of research conceptualized to provide alternative and better methods of treatment for cases, as osteomyelitis where avascular zones prevent the delivery of drugs from conventional routes of administration. Drug-loaded polymers and calcium phosphates as hydroxyapatites have been tried earlier. Bioactive glasses are bone-filling materials used for space management in orthopedic and dental surgery. A new bioactive glass (SSS2) was synthesized and fabricated into porous scaffold with a view to provide prolonged local delivery of gatifloxacin and fluconazole as suitable for the treatment of osteomyelitis. The new SSS2 was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses. In addition, the bioactivity of the SSS2 glass and resulting scaffold was examined by in vitro acellular method and ascertained by FTIR and XRD. The pore size distribution was analysed by mercury intrusion porosimetry and the release of drugs from scaffolds were studied in vitro. The glass and the resulting scaffolds were bioactive indicating that they can bond with bone in vivo. The scaffolds were porous with pores predominantly in the range of 10-60 μm, released the drugs effectively for 6 weeks and deemed suitable for local delivery of drugs to treat osteomyelitis.     

Rubrene/TPD表面及其界面的AFM和XPS研究

在indium-tin-oxide(ITO)玻璃上采用多源蒸发的方法制备了红荧烯(Rubrene)/TPD样品。由原子力显微镜(AFM)得到的表面形貌图显示Rubrene膜具有良好的均匀性。利用X射线光电子能谱仪(XPS)研究了两种材料表面和界面的电子态。由Rubrene/TPD的表面分析可知,C1s精细谱中有3个峰最强的峰是由氧化造成的,而不是对应于芳香碳(284.55eV)。空气中的O2和H2O扩散到样品里形成O1s峰。用氩离子束溅射剥蚀表面,随着时间的增长,芳香碳对应的峰越来越强,282.45和289.62eV处的峰则迅速消失,当溅射时间超过4920s时,在2847eV处引入了一个新的峰,对应于C—N键。O1s峰迅速减弱是因为氧沾污的去除。N1s谱中的N—C键缓慢增强,到达界面附近时峰的强度变得稳定。C1sN1s和O1s谱中都有峰发生化学位移。     

Hydroxybutyl chitosan thermo-sensitive hydrogel: a potential drug delivery system

Drug delivery mediated by hydrogel has shown great promise in controlled drug release field. We report here the development of a hydroxybutyl chitosan (HBC) thermo-sensitive gel to deliver doxorubicine hydrochloride (DOX·HCl) for cancer treatment. Concentrated HBC aqueous solution could transform into hydrogel within 30 s after injection under physiological temperature in non-chemical fashion. The properties of the HBC gels including chemical structure, surface morphology, and rheologic properties were studied. Gelation temperature and gelation time of HBC could be adjusted by HBC concentrations. The gel erosion rate in vivo was faster than solubilization rate in vitro. The mild inflammatory response caused by implantation of the hydrogel was acceptable. The DOX·HCl (1 mg/ml) loaded HBC gels displayed slow release rates that were independent of the HBC concentration, and significantly reduced viability of 4T-1 cells compared with the HBC gels after 1 day incubation. These results indicate that thermo-sensitive HBC hydrogels have promising potential as an injectable drug carrier for pharmaceutical applications.     

Hydrogels based on chitosan and dextran as potential drug delivery systems

The release of human growth hormone (GH) from bioartificial polymeric materials in the form of hydrogels, was measured in vitro for up to 3 weeks. Poly(vinyl-alcohol) (PVA) was blended, in different ratios, with two biological polymers, dextran and chitosan respectively. These blends were used to prepare hydrogels, using a freeze–thawing method. The hydrogels were loaded with GH, and their potential use as delivery systems was investigated. The release with time of PVA, in aqueous medium, was also monitored and evaluated. Scanning electron microscopy was used to investigate the structure of the hydrogels. The results obtained indicated that GH can be released from both dextran/PVA and chitosan/PVA hydrogels. The initial GH concentration used for sample loading affected the total quantity of GH released but not the pattern of release. The amount of GH released was affected by the content of the biological component. The percentage of PVA released was low but it was, however, related to the content of chitosan and dextran in the blends. ©1999 Kluwer Academic Publishers     

Preparation and antibacterial activity of chitosan microshperes in a solid dispersing system

In this study, we investigated the interface contacting inhibition behaviors of chitosan against bacterial in the dispersing state. For that purpose, chitosan microspheres (CMs) in the dispersing state was prepared by the emulsification cross-linking method. The CMs had smooth surface and spherical shape with the diameter of about 124 μm. They were stable after sterilization at 121°C and 150 kPa for 20 min. The CMs had similar antibacterial activity to that of chitosan in the solution form. Their antibacterial activities increased with the increase of the CM concentration, while decreased with the increase of pH of the system. It was found that the CMs with the degree of deacetylation (DD) of 63.6% exhibited the highest antibacterial activity, while the CMs with the DD of 83.7% exerted the lowest antibacterial activity among the three tested samples.     

Preparation and antibacterial activity of chitosan microshperes in a solid dispersing system

In this study, we investigated the interface contacting inhibition behaviors of chitosan against bacterial in the dispersing state. For that purpose, chitosan microspheres (CMs) in the dispersing state was prepared by the emulsification cross-linking method. The CMs had smooth surface and spherical shape with the diameter of about 124 ?m. They were stable after sterilization at 121°C and 150 kPa for 20 min. The CMs had similar antibacterial activity to that of chitosan in the solution form. Their antibacterial activities increased with the increase of the CM concentration, while decreased with the increase of pH of the system. It was found that the CMs with the degree of deacetylation (DD) of 63.6% exhibited the highest antibacterial activity, while the CMs with the DD of 83.7% exerted the lowest antibacterial activity among the three tested samples.